Cathodoluminescence characterization of GaN quantum dots grown on 6H–SiC substrate by metal-organic chemical vapor deposition

The luminescence properties of GaN quantum dots (QDs) were characterized by cathodoluminescence (CL) at room temperature via spectroscopy and monochromatic imaging. The correlations between CL results and the QD geometry measured by atomic force microscopy (AFM) were discussed considering the quantum confinement and built-in electric field in the GaN QDs. We demonstrated that CL characterizations supply abundant information about a QD system, e.g. the exciton diffusion length and the ratio of radiative recombination efficiency in the wetting layer and QDs.